From Unambiguously Defined Geometry to the Perfect Quality Control Loop

At the CIRP General Assembly 1986 Vectorial Tolerancing, a model for a quality control loop with a real three dimensional correction was presented [4]. In the fifties we learned how to control an automatic lathe by statistical quality control. We were successful, because there are only one dimensional features [1]. In this cases the calculated deviations could be used directly as a correcting value. In the milling process each feature of a geometric element, like the position and the direction requires up to two correcting procedures. Now such a quality control loop has been successfully built. On the basis of vectorial defined workpiece geometry and the machine kinematics, the NC data for a five axis milling machine and a co-ordinate measuring machine is being produced. After manufacturing the workpiece, the actual geometry is measured, and from it the correction values are calculated. The regulation of the workpiece geometry results from the feedback of the correction values into the planning process.